Do you have any of the resources links you used on Pixelation :D, I am having some trouble finding tutorials. Where did you start when you where looking into creating your own tilesets :)
The pixelation is community for pixel artist. However, Tileset aren't necessary to be pixel art. You can for example create a tileset with digital painting or vector image.
If you want to make tiles you need to learn how to tiling, grid, etc. The youtube video that I mentioned before was my starting point. It explain how the tileset works and how to tiling them.